The Nonsuch line of catboats is a series of popular cruising sailboats built between 1978 and the mid-1990s by Hinterhoeller Yachts in St. Catharines, Ontario. They are popular in North America, with over 950 boats built. The Nonsuch class was named after the Nonsuch that was the first trading vessel of Hudson's Bay Company, which in turn was named after the Baroness Nonsuch, a mistress of King Charles II of England.

A catboat is a sailboat with a single sail on a single mast set well forward in the bow of a very beamy and (usually) shallow draft hull. Typically they are gaff rigged, though Bermuda rig is also used. Most are fitted with a centreboard, although some have a keel. The hull can be 3.7 to 12.2 metres long with a beam half as wide as the hull length at the waterline. The type is mainly found on that part of the Eastern seaboard of the USA from New Jersey to Massachusetts.